This option would be great. To be able to display titles in foreign languages, nothing more.
Because most of the time, foreign titles are very different with the translation of english titles.
I don’t suppose it would require any translation work on the part of the Trakt team, because it works when I search a movie or TV show with a French title. But as the results are only in English, I have to rely on the poster (when I know it) to find the right one.